Process of producing hydrogen.



B. SPITZER.

PROCESS 0F PRODUCING HYDROGEN.

API'LICATxoN FILED man, 1914.

Patented Nov. 24, 1914.

UNITED STATES PATENT OFFICE.

BERNHARD SPITZER, OF BERLIN-WILMERSDORF, GERMANY, ASSIGNOR. TO BERLIN- ANHALTISCHE MASCHINENBAU-AKTIEN-GESELLSCHAFT, 0F BERLIN, GERMANY,

A CORPORATION OF GERMANY.

PROCESS 0F PRODUCING HYDROGEN.

Patented Nov. 24, 1914.

Application led March 12, 1914. Serial No. 824,335.

To all whom, it may concern:

Be it known that I, BERNHARD SPrrzER, a citizen of the Empire of Germany, and a resident of Berlin-Wilmersdorf, Germany, have invented certain new and useful Improvements in the Process of Producing Hydrogen, of which the following is a specification.

My invention relates to improvements in the process' of producing hydrogen, and more particularly to the process in which the hydrogen is produced by causing steam 'to act on iron or iron sponge at high temperature. As is well-known in the art, in this process the metallic iron is oxidized into magnetite. If the latter is treated at high temperature with reducing gases such as carbonmonoxid, producer gas, water gas, or the like, the iron oxid is again reduced into metallic iron which can again be used for producing hydrogen.

The iron or the iron ore can be heated directly in a shaft by passing burning gases through the same which give off their heat to the charge of iron or iron ore. On the other hand the heat which is necessary in the oxidizing or reducing processes ,can be supplied to the iron or iron ore indirectly by bringing the iron or iron ore into retorts which are externally heated by heating gases. For directly heating the iron or iron ore shafts are'used into which the material is charged for being heated therein. Thereupon, for producing hydrogen reducing gases are passed through the hot charge of iron ore which is thereby reduced into metallic iron, whereupon ,steam is passed through the charge, so that the iron is again transformed into magnetite, and hydrogen is set free. This process is objectionable in various respects, so thatit has not been carried out in a commercial way. In each case, the same gas has been used both for heating the shaft and reducing the iron ore, that is either producer gas or water gas. Careful experiments have disclosed the defects of this process.

Producer gas is very suitable for heating the shaft when it contains ore, because by reason of its low heating capacity it assures a uniform distribution of the heat through the whole charge of the shaft, and a superheating of parts of the charge is not possible. However in the reducing process producer gas is less available. By reason of its low percentage 1n carbonmonoxid its reducing actlon 1s small, and the said reducing action 1s further diminished, because the gas carries along about 70 per cent. of inactive gases, such as nltrogen, and carbonio acid, by reason of whlch the active gas is brought to action only in a diluted state and therefore w1th less energy. As the actual amount of the reducing gas within the shaft is small, large amounts thereof are necessary for reduclng the iron ore, so that the reducing gas passes through the charge of the shaft at high velocity. Careful experiments have shown, that the high velocity of the gas is exceedingly objectionable in the reducing process. On the one hand the amount of the reducinggas which is consumed in the process is considerably increased above what is necessary theoretically, and on the other hand the amount of hydrogen which is produced within a certain time in the following oxidizing process is much below what it would be if the gases had passed through the charge during the reducing process at of heat which is taken from the charge ofV iron, which amount is larger than it would be more concentratedreducing gases were use If in the heating and reducing processes instead of producer gas a gas is used which is comparatively rich in reducing agents, for instance, water gas, the reduction of the iron ore is effected in a better way. But the heating effect of the gases is such and it extends over such a limited part of the shaft, that the iron melts together at the inlet of the water gas and is in part made inactive by the reduction of its surface, while other parts of the charge are not suiciently heated. Besides the use of Water gas is inconvenient and expensive, because itis produced in an intermittent operation and therefore a storing chamber is necessary for balancing the production and the consumption. Furthermore, the direct `heating of iron ores in shafts was heretofore objectionable, because the reducing ases which are directly supplied to the sha wlthout being first purified cover the iron ore by reasonv of their percentage in sulfur with a coating of iron disullid which prevents the access of the steam to the ore and renders the charge useless after a comparatlvely short time. Besides the iron disulhd has a lower melting temperature than the iron ore,.so that it causes the formation of lumps which interfere with the passage of the reducing gases. When the reducing gases are brought in contact with the charge ofeiron carbon 1s precipitated, whereby the efficiency of the 1ron ore is impaired, unless the said carbon is again consumed when hydrogen 1s belng produced, that is to say, when steam is passed through the charge, which carbon 1s carried along by the hydrogen 1n the form of carbonio acid so as to render the hydro.- gen impure. After having thus found out the reas'ons for the defects of the process 1 have been enabled to improve the process in such a way that the injurious edects ofproducer gas and water gas are avoided, and that the improved process can be carried out in a commercial way.

in my improved process the iron ore 1s heated by means of producer gases which are particularly suitable for the process, and the iron ore is reduced by means-of water gas which isA produced in the same generator as the producer gas. The 4heating of the charge of iron ore or the combustion of the producer gas is effected within the shaft containing the iron ore and with a slight excess of air, so that the deposit of carbon which is produced duringthe reduction of the iron and the iron disulfid are removed by using an excess of air when heating the charge after the formation of the hydrogen, so that the injurious e'ect of the carbon and irondisuliid is removed. This process is furthermore advantageous in this respect, that no receptacles for storing the gases are necessary, although different gases are used in the process successively.

Experiments made with my improved process have shown, that the use of superheated steam is particularly advantageous in the oxidizing process, because the amount of hydrogen which is produced within a certain time is so much the greater the higher the temperature of the steam is.4 Preferably the steam is superheated by means of the burnt producer' gases which escape from the shaft and by the combustion of the reducing ases which have not been consumed in the s aft.

1n order that my invention be more clearly understood an apparatusl suitable for putting the same into e'ect hasbeen shown in the accompanying drawing, in which a vertical section of the apparatus -is shown. 111 the example shown in thedrawing the initiates generator 1 compressed air can be--supplled from a blower 3 and through a pipe 11. 'llhe fuel is charged into the generator 1 through K an opening 5 provided alt the: top of the generator and adapted to be closed by a lid 5', and above the said opening there is a chimney 6. '.llhe pipe 4 is equipped with a valve 7, and in front of the said valve a pipe 8 is branched on from the pipe 4 which leads to a receptacle 9 providinga shaft for receiving the charge of ore 23. 'lio the lower part of the generator 1 a steamv supply pipe 10 is connected which is adapted ,to be closed by a cock valve 11. The gas produced within the generator is discharged through an outlet 12. rihe shaft 9- for receiving the ore is likewise provided at its top with an open-v ing 13 which is adapted to be closed by a lid the gas generator 1 and the shaft 9 for the ore a purifier 22 is provided which is adapted to hold back the ashes and other impurities which are carried along by the gases coming from the generator 1.

When starting the operation of the apparatus the fuel such as coke is ignited and brought to high temperature by supplying compressed air thereto from the blower 3. During this blowing period the lid 5 is open, so that the combustion gases can escape through the chimney 6. The valves 17 and 19 are closed. Afterqthe fuel hasbeen sufficiently heated the valve 17 is opened and the lid 5 is closed. Now producer gas is discharged from the generator 1 through theA pipe 12, passes through the purifier 22 with? in which ashes and dust are held back, and is admitted to the shaft 9 and to the ore through the opening 14. Simultaneously therewith compressed air is admitted t0 the shaft 9 from the blower 3 through the 'pipe 16, thelopen valve 19, and the opening 16, so- 'tllat the producer gas is burnt within the vs a t.

The hot gases of combustion How through the charge of ore from above and downward, and esca e through the pi e 20, and into the atmosphere, the valve 21 eing open, or they are supplied to an apparatus for superheating steam. 'llhe supply of the air for supporting combustion to the .shaft 9 is regulated by means of the valve 19 in such a way, that there is a'v slight excess of air for combustion; 1f the charge of ore Within the shaft 9 has heen'brought to the desired temperature, that is to about 700 or" 800 degrees centigrade, the valves 19 and 7 f are closed, so that the air supply to the gen ico ilo

erator as well as to the shaft is interrupted.

Now the cock valve 11 is opened and steam is admitted to the generator 1 through the pipe 10. By the formation of the producer gas which is necessary for heating the shaft 9 and the ore contained therein the mass of fuel within the generator has been brought to the temperature which is necessary forV transforming the steam into water gas. Therefore the same gas generator 1 which during the -first stage supplies the producer gas to the shaft 9 for heating the ore contained therein is used subsequently for pro/ ducing the water gas which is necessary for ore only a part of the combustible parts thereof are used for reducing the ore. Therefore the waste gases which escape from the shaft through the pipe 20 can be used for superheating steam. After the iron ore has been reducedthe valve 11 provided in the steam supply to the gas generator 1 is closed, and the valve 18 of the steam `supply 15 to the shaft 9 is opened. Now the steam passes through the pipe 15 and into the shaft 9, where-i-t ows downward through the mass 23 of iron sponge. This causes the iron sponge to be oxidized by the steam, and the hydrogen which is thus produced escapes through the pipe 20 to a purifier and" a storage receptacle. Tn the meantime the temperature within the mass of ore has fallen off, and it must be reheated and reduced, this process being carried out in the same way ,as has been described above.

For a better distribution of the heat within the shaft containing the ore vthe steam may be conducted through the mass of ore alternately from above downward and from below upward.

Where the size of the generator is not sufficient to produce the amount of water gas which is necessary in the process in one step the reduction may be conducted in such a way, that the first rough reduction is effected by producer gas, while the final reduction is effected by water gas.

I claim: Y

1. The herein described process of producing hydrogen which consists in heating a mass of iron ore by means of producer gas and air, reduclng the same by means of water gas, and passing steam through the same.

2. The herein described process of producing hydrogen which consists in successively making producer gas within a generator, passing the prodiyr gas which is thus obtained together with air for supporting combustion through a mass of ore for heating the same, passing steam through the genera.

tor for producing water gas, conducting the water gas which is thusproduced through the mass of ore for reducmg the same, and

passing steam through the mass of reduced iron ore.

3. The herein described process of producing hydrogen which consists in heating a mass of iron ore by means of producer gas and air, reducing the same successively by means of producer gas and water gas, and passing steam through the same.

4. The herein described process of producing hydrogen which consists in successively making producer gas within a generator, passing the producer gas which is thus obtained together with air for supporting combustion through a mass of ore for heating the same, interrupting the supply of air to the mass of ore while continuing the supply of producer gas for effecting a preliminary reduction, passingsteam through the generator for producing water gas, conducting the water gas which is thus producedthrough the mass of ore for finally reducing the same, and passing steam through the mass of reduced iron ore.

In testimony whereof, I have signed this specification in the presence of two subscribing witnesses.

BERNHARD SPITZER. Witnesses: i HENRY HAsrEn,

WoLDEMAn HAUPT. 

